Electric furnace.



S. P. HALL. ELECTRIC FURNACE.

APPLICATION FILED JUNE 1 1908. M

Patented Mar. 9, 1909.

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SAMUEL F. HALL, OF NIAGARA FALLS, NEW YORK, ASSIGNOR TO NORTON UOMlANY, Ol WORCESTER, lVl'ASBAUHUSETTS, A CORPORATION OF MASSAUHUSETJS.

ELECTRIC FURNACE.

Specification of Letters Patent.

rammed March 9, 1909.

Application filed June 1, 1908. Serial No. 136,125.

To all whom it may concern:

Be itknown that I, SAMUEL I HALL, a citizen of the United States, residing at Niagara Falls, in the county of Niagara and" State of New York, have invented certain new and useful Im rovements in Electric Furnaces, of which the following is a specification.

The object of this invention is to provide an electric furnace having a smelting chamber wherein the charge or product may be subjected to more nearly uniform temperature conditions than are obtainable in the usual constructions. In electric furnaces of the type wherein one or more electrodes depen or project into a crucible or smelting chamber, and more particularly when the walls of the smelting chamber are watercooled, the region around andbetween the electrodes, or the interior portion of the charge, is subjected to a considerably higher temperature than the external or surrounding portions; and this results in certain cases in objectionable inequalities in the rate of conversion or in the character of the product.

According to the present invention means are provided for abstracting heat from those portions of the charge or product which are normally subjected to the highest temperature, whereby an equalizing effect is secured.

A preferred form of apparatus embodying the invention is shown in the accompanying drawings wherein: Figure 1 is a central vertical section of one form of electric furnace on line 1-1 of Fig. 2; and Fig. 2 is a horizontal section on line 22 of Fig. 1.

Referring to the drawings, 1 represents a hearth which may be vertically movable, being carried by the plunger 2 of a hydraulic or other elevator. The hearth 1 is suror lining 3, carbon. This bed is surrounded bya peripheral metal channel 4 adapted to receive the metallic shell 5 forming the exterior. wall of the furnace casing and to collect and discharge the cooling water flowing from perforated pipes 6 mounted on and surrounding the upper portion of the shell.

The water-cooled shell 5 is removable,.and'

may be lifted from the hearth or held during the descent of the hearth, as is well under- 7 for convenience in handling.

8, 8 re present carbon or graphite electrod es of opposite polarity depending into the furnace chamber.

In the central portion of the bed 3 isa metallic cup or basin Qada ted to receive the lower open end of a tubu ar metal shell 10 which constitutes the interior wall of the furnace casing and which in the form illustrated converges downwardly. The inner wallfaces of the shell 10 are adapted to be cooled by water supplied from perforated pipes 11 suitably supported at the upper portion of the casing, the basin 9 collecting thewater and discharging the same through a pipe 12. The walls of the inner shell 10 are preferably so inclined as to facilitate the separation of the product when the. hearth is lowered. The inner shell 10 may be provided with lugs 13.

In operation the material to be treated, which may be hydrated or anhydrous alumina, is charged into the furnace casing between the exterior and interior walls thereof, and is fused by the electric current passing between the electrodes in the manner commonly practiced in this art, both exterior and interior walls being adequately water-cooled. At the close of the operation the hearth is lowered to expose the product which-may then be removed and treated in the usual manner.

I claim: Y

1. An electric furnace comprisin a hearth, a casing separable therefrom and aving inclined exterior and interior walls, and means for cooling said walls, substantially as described.

2. An electric furnace comprisin a furnace chamber having exterior wal s, elec trodes of op osite polarity within said chamber, a plurality of interior Walls between said electrodes, and means for cooling said interior Walls, substantially as described.

3. An electric furnace comprising a furnace chamber, spaced electrodes of opposite polarity therein providing an intermediate heating zone, an open well between said electrodes, and means for cooling the walls of said well, whereby a compgratively uniform temperature is obtained t oughout the furnace chamber, substantially as described.

4. An electric furnace comprising a fur stood in the art, and is provided with lugs.

15 phere, electrodes oppositely disposed with nace chamber having exterior and interior I respect to said interior Walls, and means for Walls, said Walls being exposed on one side cooling said interior Walls, substantially as to the charge and on. the other side to the described. atmosphere, substantially as described. 7 An electric furnace comprising a'l'urnace 5. Anelectric furnace comprisingalurnace chamber having exterior and interior Walls, 3

chamber having exterior and interior walls, said walls being exposed on one side to the said Walls being exposed on one side to the charge and on the other side to the atmoscharge and on the other side to the atmosl phere, and means for cooling said exterior phere, and means for cooling said interior and interior Walls. 10 wells, substantially as described. In testimony whereof, I aflix my signa- 25 6. An electric furnace comprising afurnace ture in presence of two Witnesses. chamber having exterior and interior Walls, i SAMUEL F. HALL. said Walls being exposed on one side to the Witnesses: charge and on the other side to the atmos- KATHRYN CALDWELL,

CARL E. TUQKER. 

